Heat exchanger



Sept. 28, 1965 KATSUYUKI OHNODA ET AL 3,208,510

HEAT EXCHANGER Filed Aug. 2, 1965 Fig./.

United States Patent 3,208,510 HEAT EXCHANGER Katsuyuki Ohuoda,Mizuho-ku, Nagoya, and Masaya Fujisaki, Narumi-gho, Aichi-gun,Aichi-ken, Japan, assign'ors to Shin-Mitsubishi Jukogyo KabushikiKaisha, Tokyo, Japan. Filed Aug. 2, 1963, 'Ser. No. 299,611 Claimspriority, application Japan, Mar. 12, 1963, 38fi11,417 6 Claims. (Cl.165-51) The present invention relates to heat exchange apparatus andmore particularly to heat exchange apparatus for engines such asturboengines, turboprops, jet engines, and the like.

In recent aircraft, a conventional heat source is required for thepurpose of removing ice from the plane as well as for providing heatinside the plane. In large jet planes for passengers, bleed air from thejet engine is utilized for this purpose, but in small turbopropairplanes, due to a shortage of bleed air, another heat source isnecessitated.

Generally, in order to meet the deficiency of the heat source, theexhaust gas from the engine has been used to operate a heat exchangeapparatus for heating the air utilized for said purpose. However, suchheat exchange apparatus is bulky often causing rearrangement ofequipment.

Therefore, it is an object of the present invention to provide heatexchange apparatus without such defects as mentioned above.

Another object of the present invention is to provide heat exchangeapparatus incorporated in the tail pipe of the engine as a part thereof.

To this end, there is contemplated heat exchange apparatus whichcomprises a tail pipe, a cylindrical cover surrounding said tail pipeand defining a space between said tail pipe and said cover, an exhaustgas intake device providing communication between the inside of saidtail pipe and said space, an exhaust gas outlet device to permit outflowof exhaust gas from said space, an intake device and an outlet devicefor air to be heated, each of which opens into said space, and heattransfer means mounted in said space between the tail pipe and the coverand defining closed chambers in said space, each in communication with arespective air device, said heat transfer means including means forconveying air from the chamber associated with the air intake device tothe chamber associated with the air outlet device in heat exchangerelation with said heated gases, but without contacting the same.

In the present invention as mentioned above, the exhaust gas and the airto be heated, both being fed to the space, are separated from each otherin said chambers. Consequently, the air inducted into the space by theintake device and discharged from said outlet device may be heated, whenit passes in said space between the chambers, by the exhaust gas of hightemperature inducted from the exhaust gas intake device, therebyeliminating the need for a separate heat source. Furthermore, theexhaust gas and the air to be heated are separated from each other,eliminating any mixing together thereof in said space.

Further, according to the present invention, since a part of the tailpipe itself constitutes the heat exchange apparatus, both space and costfor equipment may be economized, compared with known heat exchangeapparatus.

Therefore, it is an advantage of the present invention that space andcost for equipment can be reduced.

Other objects and advantages are obtained by the present invention aswill be apparent from the following de- "Ice scription taken inconnection with the accompanying drawings, in which:

FIG. 1 is a longitudinal side section showing an embodiment of thepresent invention;

FIG. 2 is a vertical cross section, along the line lIII in FIG. 1; and

FIG. 3 is an enlarged perspective view of a portion of the device ofFIG. 1 and FIG. 2.

In the drawings, 1 is a tail pipe of a turboprop engine or a jet engine2, the outer periphery of which is circumferentially surrounded by acylindrical cover 4 to form an annular space covering openings 3 in thetail pipe. Exhaust gas from inside the tail pipe 1 passes through theopenings 3 formed in said tail pipe 1. At the tail end of saidcylindrical cover 4, an outlet device for exhaust gas is constituted ofa port 6 having a butterfly valve 5 fitted therein.

In the diametrically opposed upper and lower ends of said annular space,are formed chambers 7 and 7, having longitudinal side plates 11, 11'respectively connected to the cylindrical cover 4 and the tailpipe 1.Transverse end plates 12, 12 extend across the annular space betweenside plates 11, 11' to thereby completely isolate the chambers 7, 7'from the flow of exhaust gas. Between said opposed side plates of theupper and lower chests 7, 7 are two groups of a number of stainlesssteel air conduits 8, 8' which arcuately curve and peripherally extendalong the said annular space, said conduits being connected to the sideplates 11, 11 and open into said chambers 7, 7' as seen in FIG. 3.

Moreover, on said cylindrical cover 4, an intake port 9 and an outletport 10 for air to be heated are arranged respectively communicatingwith the chambers 7, 7 The chamber 7' and the intake port 9, and thechamber 7 and the outlet port 10 are respectively in communicationwhereby the air can flow from port 9 to port 10 via conduits 8 and beheated by the exhaust gases when passing through said conduits.Accordingly, when the butterfly valve 5 fitted to the inside of theexhaust port 6 for the exhaust gas is opened, the high temperatureexhaust gas from the engine flows into the annular space through theopenings 3 of the tail pipe 1, and, passes through the air conduits 8,8', to be discharged from the exhaust port 6 via the butterfly valve 5;on the other hand, the air introduced through the intake port 9 into thechamber 7' in said annular space passes through the conduits 8, 8, whilebeing heated by said exhaust gas of high temperature passing outsidethereof, and flows into the chamber 7 and then is discharged from theoutlet port 10 and utilized as desired. Thus, the operation is effectedwithout mixture of the exhaust gas and the air while heat exchangebetween the exhaust gas and the air is satisfactorily achieved.

In the abovementioned embodiment, though the tubular walls of conduits8, 8 are utilized as heat-transfer walls, various other constructionsmay optionally be adopted as heat transfer walls.

It will be clear to those skilled in the art that the invention is notlimited to the specific construction disclosed herein, but coversvarious modifications and variations without departing from the spiritof the invention as defined in the accompanying claims.

What is claimed is:

1. Heat exchange apparatus for the tail pipe of an engine employing thetail pipe itself as a part of the apparatus, said apparatus comprising acover including a cylindrical portion, said tail pipe having an outersurface, said cover being on and surrounding said outer sur face of thetail pipe to define therewith a closed space between the cover and tailpipe, said tail pipe having an opening therein establishingcommunication between the interior of the tail pipe and the said spacesuch that exhaust gas within the tail pipe will flow into said space,outlet means on said cover at a location spaced from said opening forthe selective discharge of exhaust gas from within said space wherebywith said outlet means open exhaust gas will flow through said space,means defining enclosed chambers at diametrically opposed locations insaid space at a position between the opening in the tail pipe and theoutlet means, said chambers being isolated from the passage of exhaustgas, said cover having an opening in communication with a respectivechamber, a plurality of curved heat exchange tubes extending between andin communication with said chambers for the passage of a fluid, one ofsaid chambers constituting an inlet for the fluid, the other of thechambers constituting an outlet for the fluid, the exhaust gases flowingaround said tubes and in heat exchange relation with the fluid in saidtubes as the exhaust gases flow from said opening in the tail pipe tothe outlet means, the fluid flowing from said inlet to the outlet viasaid tubes and being heated by the exhaust gases during said flowing,said means defining the chambers including, for each chamber a pair ofspaced longitudinally extending side plates secured between the outersurface of the tail pipe and the cylindrical portion of the cover andcoupled to the heat exchange tubes to permit passage of fluid betweenthe tubes and the chamber.

2. Heat exchange apparatus comprising a tail pipe adapted for conveyingheated gases, a cylindrical cover surrounding said tail pipe anddefining a space between said tail pipe and said cover, an exhaust gasintake device providing communication between the inside of said tailpipe and said space whereby heated gas from said tail pipe can flowoutwardly and enter said space, an exhaust gas outlet device in saidcover to permit outflow of exhaust gas from said space, whereby heatedexhaust gas can pass through said space, an intake device for air to beheated and an outlet device on said cover for heated air, each of whichopens into said space, heat transfer means mounted in said space betweenthe tail pipe and the cover and defining closed chambers in said spaceeach in communication with a respective air device, said heat transfermeans including means for conveying air from the chamber associated withthe air intake device to the chamber associated with the air outletdevice in heat ex- 4- change relation with said heated gases but withoutcontacting the same, said heat transfer means isolating the chambersfrom the flow of exhaust gas.

3. Apparatus as claimed in claim 2, wherein said exhaust gas intakedevice is constituted by a plurality of circumferentially arrangedopenings in said tail pipe.

4. Apparatus as claimed in claim 2, wherein said air intake and outletdevices are diametrically located on said cover.

5. Apparatus as claimed in claim 2, wherein said means for conveying airbetween said chambers comprises a plurality of conduits extendingbetween said chambers for the conveying of air which is heated by thepassage of gas past said conduits.

6. Apparatus as claimed in claim 5, wherein said heat transfer meanscomprises a pair of longitudinal side plates between the cover and tailpipe bounding each chamber, said side plates supporting the conduits andenabling the latter to open directly into the respective chambers,transverse end plates positioned between the cover and tail pipe andextending between the side plates of each chamber to combine with theside plates to completely isolate the chambers from the flow of exhaustgas.

References Cited by the Examiner UNITED STATES PATENTS 1,068,094 7/13Bailey et a1. 23712.3 1,851,691 3/32 Yaeger 156 X 2,458,159 1/49Goldthwaite 165-125 X 2,519,496 8/50 Norman 165125 X 2,828,946 4/58Smith 165154 X FOREIGN PATENTS 616,659 1/49 Great Britain. 710,381 6/31France.

OTHER REFERENCES Utilization of Exhaust Heat Exchanger Installations, byP. A. Pitt, from the March 1, 1945, issue of the Aero Digest.

ROBERT A. OLEARY, Primary Examiner.

CHARLES SUKALO, Examiner.

2. HEAT EXCHANGE APPARATUS COMPRISING A TAIL PIPE ADAPTED FOR CONVEYINGHEATED GASES, A CYLINDRICAL COVER SURROUNDING SAID TAIL PIPE ANDDEFINING A SPACE BETWEEN SAID TAIL PIPE AND SAID COVER, AN EXHAUST GAS INTAKE DEVICE PROVIDING COMMUNICATION BETWEEN THE INSIDE OF SAID TAILPIPE AND SAID SPACE WHEREBY HEATED GAS FROM SAID TAIL PIPE CAN FLOWOUTWARDLY AND ENTER SAID SPACE, AN EXHAUST GAS OUTLET DEVICE IN SAIDCOVER TO PERMIT OUTFLOW OF EXHAUST GAS FROM SAID SPACE, WHEREBY HEATEDEXHAUST GAS CAN PASS THROUGH SAID SPACE, AN INTAKE DEVICE FOR AIR TO BEHEATED AND AN OUTLET DEVICE ON SAID COVER FOR HETED AIR, EACH OF WHICHOPENS INTO SAID SPACE, HEAT TRANSFER MEANS MOUNTED IN SAID SPACE BETWEENTHE TAIL PIPE AND THE COVER AND DEFINING CLOSED CHAMBERS IN SAID SPACEEACH IN COMMUNICATION WITH A RESPECTIVE AIR DEVICE, SAID HEAT TRANSFERMEANS INCLUDING MEANS FOR CONVEYING AIR FROM THE CHAMBER ASSOCIATED WITHTHE AIR INTAKE DEVICE TO THE CHAMBER ASSOCIATED WITH THE AIR OUTLETDEVICE IN HEAT EXCHANGE RELATION WITH SAID HEATED GASES BUT WITHOUTCONTACTING THE SAME, SAID HEAT TRANSFER MEANS ISOLATING THE CHAMBERSFROM THE FLOW OF EXHAUST GAS.